108 строки
4.0 KiB
Plaintext
108 строки
4.0 KiB
Plaintext
.\" -*- nroff -*-
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.\" Copyright 2013-2014 Los Alamos National Security, LLC. All rights reserved.
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.\" Copyright 2010 Cisco Systems, Inc. All rights reserved.
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.\" Copyright 2006-2008 Sun Microsystems, Inc.
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.\" Copyright (c) 1996 Thinking Machines Corporation
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.TH MPI_Fetch_and_op 3 "#OMPI_DATE#" "#PACKAGE_VERSION#" "#PACKAGE_NAME#"
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.SH NAME
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\fBMPI_Fetch_and_op\fP \- Combines the contents of the origin buffer with that of a target buffer and returns the target buffer value.
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.SH SYNTAX
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.ft R
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.SH C Syntax
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.nf
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#include <mpi.h>
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int MPI_Fetch_and_op(const void *\fIorigin_addr\fP, void *\fresult_addr\fP,
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MPI_Datatype \fdatatype\fP, int \fItarget_rank\fP, MPI_Aint \fItarget_disp\fP,
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MPI_Op \fIop\fP, MPI_Win \fIwin\fP)
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.fi
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.SH Fortran Syntax (see FORTRAN 77 NOTES)
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.nf
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INCLUDE 'mpif.h'
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MPI_FETCH_AND_OP(\fIORIGIN_ADDR, RESULT_ADDR, DATATYPE, TARGET_RANK,
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TARGET_DISP, OP, WIN, IERROR\fP)
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<type> \fIORIGIN_ADDR\fP, \fIRESULT_ADDR\fP(*)
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INTEGER(KIND=MPI_ADDRESS_KIND) \fITARGET_DISP\fP
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INTEGER \fIDATATYPE, TARGET_RANK, OP, WIN, IERROR \fP
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.fi
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.SH INPUT PARAMETERS
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.ft R
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.TP 1i
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origin_addr
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Initial address of buffer (choice).
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.ft R
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.TP
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result_addr
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Initial address of result buffer (choice).
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.ft R
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.TP
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datatype
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Data type of the entry in origin, result, and target buffers (handle).
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.ft R
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.TP 1i
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target_rank
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Rank of target (nonnegative integer).
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.ft R
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.TP 1i
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target_disp
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Displacement from start of window to beginning of target buffer (nonnegative integer).
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.ft R
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.TP 1i
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op
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Reduce operation (handle).
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.ft R
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.TP 1i
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win
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Window object (handle).
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.SH OUTPUT PARAMETER
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.ft R
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.TP 1i
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IERROR
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Fortran only: Error status (integer).
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.SH DESCRIPTION
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.ft R
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Accumulate one element of type \fIdatatype\fP from the origin buffer (\fIorigin_addr\fP) to the buffer at offset \fItarget_disp\fP, in the target window specified by \fItarget_rank\fP and \fIwin\fP, using the operation \fIop\fP and return in the result buffer \fIresult_addr\fP the contents of the target buffer before the accumulation.
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.sp
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The origin and result buffers (\fIorigin_addr\fP and \fIresult_addr\fP) must be disjoint. Any of the predefined operations for \fBMPI_Rreduce\fP, as well as MPI_NO_OP or MPI_REPLACE, can be specified as \fIop\fP; user-defined functions cannot be used. The \fIdatatype\fP argument must be a predefined datatype. The operation is executed atomically.
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.sp
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A new predefined operation, MPI_REPLACE, is defined. It corresponds to the associative function f(a, b) =b; that is, the current value in the target memory is replaced by the value supplied by the origin.
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.sp
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A new predefined operation, MPI_NO_OP, is defined. It corresponds to the assiciative function f(a, b) = a; that is the current value in the target memory is returned in the result buffer at the origin and no operation is performed on the target buffer.
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.SH FORTRAN 77 NOTES
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.ft R
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The MPI standard prescribes portable Fortran syntax for
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the \fITARGET_DISP\fP argument only for Fortran 90. FORTRAN 77
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users may use the non-portable syntax
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.sp
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.nf
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INTEGER*MPI_ADDRESS_KIND \fITARGET_DISP\fP
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.fi
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.sp
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where MPI_ADDRESS_KIND is a constant defined in mpif.h
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and gives the length of the declared integer in bytes.
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.SH NOTES
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It is the user's responsibility to guarantee that, when
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using the accumulate functions, the target displacement argument is such
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that accesses to the window are properly aligned according to the data
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type arguments in the call to the MPI_Fetch_and_op function.
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.SH ERRORS
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Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument.
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.sp
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Before the error value is returned, the current MPI error handler is
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called. By default, this error handler aborts the MPI job, except for I/O function errors. The error handler
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may be changed with \fBMPI_Comm_set_errhandler\fP; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarantee that an MPI program can continue past an error.
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.SH SEE ALSO
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.ft R
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.sp
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MPI_Get_accumulate
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.br
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MPI_Reduce
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